On Tuesday, a much-anticipated mid-level wave will arrive in the Central Plains, creating the potential for a significant severe weather episode.  Seasonally-rich moisture will continue to advect northward in response to deepening low pressure in the lee of the Rockies.  Meanwhile, a strong elevated mixed-layer (EML) will advect over the moist layer, creating the potential for strong instability.  Morning convection over Nebraska and Iowa may delay surface heating somewhat, but it is likely that – at least – strong instability will develop.

A warm front / outflow boundary looks to be the primary focus for severe weather tomorrow, though storms may fire further south on the dryline.  Given the a) strong to, perhaps, extreme instability, b) strong shear at all levels, and c) deep moisture, the potential exists for high-end severe, including tornadoes.  The greatest threat for tornadoes will likely exist along the warm front in central and eastern Nebraska.  Storm mode will be key, as upscale growth could limit the tornado potential.  Some high-resolution models hint at the development of a strong squall line – perhaps, even a derecho – not long after convective initiation.

In order to capture the initial development, we have elected to start the shift at 1 pm. We will meet in the Hazardous Weather Testbed to listen to the EFP daily briefing.

-G. Garfield
Week 4 Coordinator